Magnesium base alloy



I such as high tensileand yield strengths. nickel and from about 0.1 to 0.3 per cent of cal- 5 yield strengths. provement in ductility and strength character- 25 Nominal composition in pergaint Annealed Cold rolled magn um: remainder) 35 Yield Tensile Percent Yield Tensile Ni Ca strength in strength in elon tion strength in strength in lbs/sq. in. lbs/sq. in. in 2 ches lbs/sq. in. lbs/sq. in.

0.3 17,)0 30,!!!) 13 27,000 32,000 40 0. 8 17, [ID 32, 000 ll 23, 000 31, 000

0. 8 0. 3 2'1, M 34. 000 19 34, 000 40, (I!) 2.0 11,011 34,000 10 25, 33,000 2.0 03 23,000 35, 13 36.61!) 43,1130 6.0 29.0(11 39,!!!) 6 32,111) 38,000 6.0 0.3 -%,(XIJ 37,000 10 39,011) 46,000 40 9. o as, 000 42, 000 2 31,000 42,000

Patented Feb. 25, 1941 {QNITED STATES PATENT OFFICE MAGNESIUM BASE ALLOY Joseph D. Hanawalt and John O. McDonald, Mid- 7 land, Mich., assignors to The Dow Chemical i 'Company, Midland, Mich a corporation of LII. 0 Michigan No Drawing. Application February 1, 1940,

Serial No. 316,765

3 Claims. (01. 75-168) Theinvention relates to magnesium base alloys of properties, such as the most desirable ductility and more particularly concerns an alloy of this for forming operations, as well as exceptionally nature having a high degree of iormability assohigh tensile and yield strengths, is obtained when ciated with other desirable physical properties, the alloy contains from about 2 to 6 per cent of Magnesium basealloys are being widely used vcium. in various structural and mechanical arts where The specific proportion of each alloying metal a light weight metalis'highly desirable, such as and the total amount of alloying metals to be for use in making castings, forgings, and the employed in the new alloy depends upon ,the use 10 like. However, the use of these alloys in the for which the alloy is intended. For example, 10 rolled form to make sheet metal articles requlrin alloys where exceptionally high ductility or ing forming operations, such as bending, draw formability associated with good tensile and yield ing, and the like, has not progressed as rapidly strengths is of principal importance,'the alloy due to the fact that in general alloys having should contain from between about 2 to 4 per 15 good formability, permitting relatively sharp cent of nickel and from about 0.1 to 0.3 per cent 15 bends to be made without the article developing ofcalcium. While in those instances where high external cracks, usually have inferior strength yield and tensile strengths are of more imporcharacteristics. tance, the nickel content of the alloy may be in It is, accordingly, the principal object of the the order of from 6 to 10 per cent.

20 invention to provide a magnesium base alloy The following table lists some of the properties 2 which can be made into a rolled sheet or the of rolled sheet metal made from our new ternary like possessing a suiflcient degree of ductility or alloy and compares these properties with those iormabili'ty to be sharply bent, drawn, or otherof rolled sheet made from related binary alloys. wise shaped, while having excellent tensile and A comparison oi. the properties illustrates the im- Other objects and advantages will be apparent istics of the new alloy over that 01' the closely reas the description oi! the invention proceeds. 'lated binary alloys. In the table, the per cent Our invention resides in the discovery that a Y elongation is to be regarded as a measure of the magnesium base alloy composed of from about ductility or formability of the specimen.

1 to 10 per cent of nickel and from about 0.01 to 1 The properties in the above table listed under per cent 0! calcium, the balance being substanthe section headed by the term anneale d" were tially all magnesium, is endowed with the aforeobtained by first rolling the alloys at a temperamentioned properties.- While the properties of ture between about 600-800 F. and thereafter good formability oiductility associated with high annealing them at various temperatures in the tensile and yield strengths are manifest over the temperature range from 400 to 800 F. The entire range of composition indicated, we have properties selected for the table were those of found that in general the preferred combination the annealed specimens which exhibited the 55 maximum elongation. The properties listed under the section headed by the term "cold rolled" were obtained by subjecting specimens of the alloys which had been hot rolled at from 600 to 800 F. to additional rolling in the cold state to bring about a total reduction of from 2 to 10 per cent. The properties selected for the table were those of the cold rolled specimens which showed the greatest tensile and yield strengths,

while having at least a 1 per cent elongation in 2 inches. By a comparisonv oi the properties listed in the above table, it will be observed that the combined properties of the new ternary alloy are superior to those of the related binary alloys having similar percentages of alloying ingredients. For example, it will be noted that the compositions containing the lower percentages of alloying ingredients show a maximum elongation or ductility, while having good yield and tensile properties in the annealed state; while those having higher percentages of alloying ingredients show good ductility coupled with exceptionally high yield and tensile strengths. Similarly, it will be noted that the properties of the cold rolled specimens made from our new alloy show improved strength characteristics. These improvements are characteristic of the new alloy throughout the range of alloying ingredients indicated. I

While the new alloy is most useful in-the wrought form, such as sheets, due to its form ability characteristics, it may also be suitably used for making castings, forgings, extruded forms and the like.

The alloy may be compounded in any of the ways known to the art, such as by adding the alloying ingredients to molten magnesium under a suitable flux. The flux should be substantially free of magnesium chloride if the calcium content in the alloy is to be above 0.3 per cent. In those instances where an alloy is to be compounded containing less than 0.3 per cent of calcium, magnesium chloride may be present in the flux without exerting undue deleterious effects, but in this case it is usually preferable to add the calcium last without too much stirring or agitation in order that loss of calcium into the flux may be substantially prevented.

We claim: I

1. A magnesium base alloy containing from about 1 to 10 per cent of nickel and from 0.01 to 1 per cent of calcium the balance being magnesium.

2. A magnesium base alloy containing from 2 to 6 per cent of nickel and from 0.1 to 0.3 per cent of calcium, the balance being magnesium.

3. A magnesium base alloy containing from 6 to 10 per cent of nickel and from 0.1 to 0.3 per cent of calcium, the balance being magnesium. JOSEPH D. HANAWALT. JOHN C. McDONALD. 

